Pendulum actuated electric clock



June 23, 1953 L. ROBERT PENDULUH ACTUATED ELECTRIC CLOCK Filed Dec. 20,1948 r x 0. 2.. Tm mm Mo N m W m x m W m 3 A m 1 W Patented June 23,1953 UNITED STATES PATENT OFFICE PENDULUM AUTlJZ'iZEiJLE-GTBIC CLOCKApplicationDecemb'er 20, 1948, Serial N'o. 66,'331 In France January16,, 1948 1 Claim. 1

This invention relates to 'ele'ctricclocks Wherein the pendulum isdriven by the action exerted by an emissive coil on a magnetized bar. lnsuch clocks it is essential to obtain the maximum isochronism of theoscillations.

Various devices have been hitherto proposed which provide means forapplying a braking effeet at the end of the oscillation to improve theabove-mentioned isochronis'm. For this purpose, three-pole magnetizedbars have been utilized, having two poles of the same sign at the endsand a third pole of the opposite sign in the middle.

Magnets have also been utilized, which are driven by an energizing coilsecured at the rest position of the pendulum.

Such arrangements are only 8fi'l01811t when the positive resistances ofthe clock mechanism are very low. It is therefore necessary to overcomethe resistances and the losses of inertia.

To overcome the disadvantages outlined above the present inventionprovides an electric clock wherein the braking action is obtained by thecombination of a central coil mounted on the clock stand and cooperatingwith a three-pole magnet having spaced-apartrecurvate, two poles of thesame sign being positioned at the spacedapart ends of said magnet whilethe third pole of opposite sign is positioned centrally of said magnet.The mechanism of the clock according to the invention is much simplifiedand necessitates but a very small number of wheels.

The oscillating movement of the pendulum ensures the tooth by toothrotational drive through the intermediary of a special pawl controlmember, of a first wheel carrying a stud adapted to actuate the minutewheel, which is, while the hour wheel journaled freely on the minutewheel shaft, is frictionally driven at regular intervals by this shaftwhen the hour wheel is released from engagement with a locking device.

Other characteristic features of the invention will become apparent fromthe following description with reference to the accompanying drawing, inwhich:

Fig. 1 is a front view of the clock mechanism partly broken away to showdetails of construction, and

Fig. 2 is a side view of same.

Fig. 3 shows the manner in which the clock journals are mounted.

Fig. 4 is an enlarged perspective view of the driving mechanism for thehour hand.

The mechanism is supported by two plates I and I. The pendulumoscillates about a spindle 2 journalled in the aforesaid plates and com-2 prises a rod "3 weighted at its lower portion :by a' cou'nterweight of:conical shape, :formed from a plurality of washers .such as 5. Thisparticular shape of counterweight reduces resistance during theoscillatory. movements.

The rod 3 'carries1under the counterweight a magnetized bar 6 havingspaced-apart .recui'vate ends, as shown in Rig. 1., and having at -:'I,,1" "two poles of same. sign and at l" a pole of opposite sign.

The distance separating the two ends I, I is equal to the length .of 'acoil '8 which has :its axis arranged horizontally and is secured to theclockcasing or base member in 3111051131011 corresponding to the rest-position of the pendulum. The pendulum :rod '3 is :causedtooscillate-by the periodic energization of the coil 8. Since the ends I,l areof the same polarity, which is :orpposite in sign to 'thepole 'Ieach will be driven out of the coil 8'upon its :energ-ization, i. :e.this action will occur when either of the poles I, l is in the coil 8,so that the oscillation of "the pendulum .is constantly energized.

The pendulum is arranged to drive :either directly or, in the case of a.large-isize clock,x by means of a fork .member, a pawl 8 mounted on anarm I0 secured to the spindle 2 of the pendulum. This pawl 9 drives atoothed wheel I I. To prevent each oscillation of the pendulum fromcausing the wheel II to be driven on more than one tooth, the pawl 9 isfast, by a common connection with a strap 35 which pivots about a shaft36, with a hook-shaped cam member l2 guided by a fixed pin I3 secured onthe plate I. Thus the engaging portion of the pawl 8 is lifted out ofmeshing engagement with the teeth when the wheel II has been rotated bya one-tooth interval. A lever I4, pivotally mounted about I5 carries apin 31 which engages the teeth of the wheel II whereby the rotation ofthe wheel I I will raise lever I4 which will connect by means of contactelement 38, on reaching its uppermost position, the terminal contacts ofthe wires I6, ll inserted in the circuit for energizing the coil 3.These wires may be concealed within the clock casing on their remainingpath.

The wheel II is fast with a pin I8 meshing with the teeth of a wheel [9so as to rotate the latter. A retaining pawl 20 is provided in order tolimit the rotational movement of wheel I9.

The shaft 2 I, carrying the wheel I9, also carries an eccentric cam 22and the minute hand 23. The hour hand 24 is fast with a sleeve 25 on 3which a ratchet wheel 26 is secured. The sleeve 25 is loosely mounted onthe shaft 2!.

A vertically arranged fork 28 is pivoted on another shaft 21; this forkhas at the end of each prong thereof a pair of pins 29 adapted to meshwith the teeth of the ratchet wheel 26.

As shown in Fig. 4, an eccentric cam 22 mounted upon the shaft 2| ispositioned for rotation between the prongs of a fork member 28. The forkmember 28 carries pins 29 which are adapted alternately to engage theteeth of ratchet wheel 26 to hold it against rotation by frictionalengagement with the shaft 2|. Rotation of the eccentric cam 22, which iseffected by the rotation of shaft 2|, causes the fork member 28 toreciprocate laterally and to release, at regular.

intervals, one of the pins 29, thereby permitting the ratchet wheel 26to rotate and then effects Ie engagement of the other pin 29 with theteeth of the ratchet wheel to hold the wheel against rotation until thenext periodic release.

This will cause the hour hand 24 to rotate at regular intervals. Withthe arrangement described one of the gearings of the conventional clockmechanism may be dispensed with.

To reduce frictional losses between shafts and their journals, thelatter are made of simple cylindrical members suchas shown at 30 in Fig.3. These cylinders engage hollow sleeves screwthreaded externally so asto be screwed into the plates. A set-pin 3| is provided for acting as acounter-pin to the end journal pin of the shaft 39.

The clock casing is formed by two uprights of any suitable material suchas wood, provided with grooves,- as at 32, for receiving both in thefront and back faces of the mechanism, glass plates 33, 34 adapted toprevent dust or other foreign substances from penetrating into themechanism. The front glass plate 33 acts as a dial. This plate. may beprovided with the conventional marks either by engraving or othermechanical or chemical action applied to the glass surface, vor byadhesively secured signs of paper or other material.

7 It will be readily understood that the embodiment describedhereinabove and illustrated in the accompanying drawing is merely givenby way of example without any purpose of limitation as to shape, size,arrangement, material utilized, etc. Various modifications may bebrought to the details of the apparatus without impairing or exceedingthe scope of the invention.

What I claim is:

electric clock comprising a pendulum, electrically-energized means foroscillating said pendulum, a minute wheel fixedly mounted on a shaft, afirst toothed wheel provided with a pin in driving engagement with thesaid minute wheel, a toothed hour wheel having circumferenti'allydisposed teeth and rotatabiy mounted upon said shaft and rotatable byfrictional engagement with said shaft, a vertically disposed fork memberhaving spaced-apart prongs pivotally mounted about a fixed point belowthe said shaft and carrying adjacent the ends of said prongs a pair ofpins engageable between the teeth of said hour wheel, an eccentric cammember mounted on said shaft between the spaced-apart prongs andengageable with the sides of said prongs to cause a regular oscillatingmovement of said forked member upon rotation thereof, and a pawl controlmeans actuated by said pendulum and actuating in turn in a tooth bytooth manner said first toothed wheel.

LEON ROBERT.

References lCited in the file of this patent UNITED STATES PATENTSNumber Name Date 120,185 Davis Oct. 24, 1871 541,840 Diehl July 2, 18951,970,412 Bates Aug. 14, 1934 2,209,858 Steiert July 30, 1940 FOREIGNPATENTS Number 7 Country Date 19,818 Great Britain of 1914 571,105France Jan. 26, 1924 479,376 France Dec. 24, 1915 677,304 France Dec. 9,1929

